Tuberculosis (TB)

Question 1

Which bacteria causes tuberculosis?

Answer 1

Mycobacterium tuberculosis complex

Question 2

Who is at a higher risk of developing tuberculosis?

Answer 2

1. Diabetics
2. HIV/cancer/organ transplants
3. Immuno-suppressed patients
4. Excessive alcohol/smoking

Question 3

What is the difference between active and latent TB?

Answer 3

Active TB: illness can occur weeks, months or years after inhaling in the bacteria

Latent TB: no illness and not infectious, the immune system regulates TB to minimal levels. It can also reactivate later in life

• Remember active TB is always symptomatic

Question 4

Which vaccine is given for tuberculosis?

Answer 4

BCG vaccine.

Question 5

Which certain populations are offered the TB vaccination?

Answer 5

1. Born in an area where TB is high
2. Working with animals that can also get TB e.g. chimps or cows
3. <15years who werent vaccinated as newborn babies
4. Been in close contact with someone who has had TB

Question 6

What are some symptoms of active TB?

Answer 6

1. Persistent cough with/without sputum, may contain blood
2. Loss of appetite/losing weight
3. Extreme fatigue
4. Fever with sweats

Question 7

What does the physical diagnosis of active TB depend on?

Answer 7

If the TB is:

1. Pulmonary
   - CT scan, x-ray
2. In the lymph nodes
   - MRI, CT scan
3. In the bones
   - X-ray, CT, MRI

All specimens are also taken for microscopy/histology

Question 8

What is the mantoux test for latent TB?

Answer 8

It is a TB skin test where tuberculin is injected and the skin is inspected for a reaction.

Positive test: if the reaction is >5mm

Question 9

How can a false positive test occur during the mantoux test?

Answer 9

The irritation produced could be from something else other than the tuberculin injected.

Question 10

What is the interferon gamma release assay (IGRA) test for latent TB?

Answer 10

it is a blood test to detect the response of WBC’s to TB antigens.

Question 11

What are the benefits of the IGRA test compared to the mantoux test?

Answer 11

False positive results are less likely to occur, and the results are much quicker.

Question 12

How is the mantoux test administered?

Answer 12

Via intradermal injection.

Question 13

What can happen after, if the mantoux test has turned out positive?

Answer 13

1. Assess for active TB
2. Consider IGRA test for more evidence
3. Offer treatment for a latent infection

Question 14

What are the treatment options for latent TB?

Answer 14

1. Sometimes does not have to be treated
2. 3 months isoniazid (300mg daily) + rifampicin (600mg daily) + pyridoxine hydrochloride (vit. B6, 10-20mg daily)
3. OR 6 months isoniazid (300mg daily) + pyridoxine hydrochloride (vit. B6, 10-20mg daily))

Question 15

Why is pyridoxine hydrochloride (vit. B6) given with isoniazid?

Answer 15

It prevents induced neuropathy

Question 16

What is the mode of action of rifampicin?

Answer 16

It inhibits DNA-dependent RNA polymerase activity, so suppresses RNA synthesis and is hence bactericidal.

Question 17

How is rifampicin taken in TB?

Answer 17

Taken on an empty stomach to allow efficient absorption.

Question 18

Why can drug interactions occur when taking rifampicin?

Answer 18

Because rifampicin is a CYP450 inducer.

Question 19

What is the mode of action of isoniazid?

Answer 19

It interferes with the cell wall synthesis and is hence bactericidal (bacteriostatic in low conc.)

Question 20

What should be monitored when taking isoniazid for TB?

Answer 20

Liver function.

Question 21

What occurs in the GI when pyridoxine hydrochloride (vit. B6) is given?

Answer 21

It is converted into its active forms

Question 22

What is the standard treatment of active tuberculosis?

Answer 22

1. INITIAL PHASE: REMEMBER ‘RIPE’
   - 4 drugs for 2 months
   - Rifampicin
   - Isoniazid (+ pyridoxine hydrochloride, vit. B6)
   - Pyrazinamide
   - Ethambutol hydrochloride
2. CONTINUATION PHASE
   - 2 drug for 4 months
   - Rifampicin + isoniazid + pyridoxine hydrochloride
   - Those with active CNS TB need to extent their treatment for 10months

Question 23

What test needs to be regularly conducted when taking ethambutol in active TB?

Answer 23

Eye assessments, to avoid severe ethambutol/isoniazid interactions (optic neuropathy)

Question 24

What needs to be monitored when taking pyrazinamide for active TB?

Answer 24

Hepatic function.

Question 25

What are rifampicin and pyrazinamide dose dependent on?

Answer 25

Weight of the patient.

Question 26

Which tablet contains all 4 TB treatments, and hence aids in patient compliance?

Answer 26

Voractive tablets - Contains RIPE drugs

Question 27

What is contained in rifinah tablets?

Answer 27

Rifampicin + isoniazid

Question 28

What is contained in rifater tablets?

Answer 28

Isoniazid + pyrazinamide + rifampicin

Question 29

When should DOT (directly observed therapy) be required in patients with TB?

Answer 29

1. Previously been treated with TB 2. History of homelessness, alcohol or drug abuse 3. Too ill to administer for themselves 4. Major psychiatric, memory or cognitive disorders

Question 30

How many drugs should be given if the patient has resistant TB?

Answer 30

6.

Question 31

How many priorities are there in the TB Action Plan for England?

Answer 31

1. Recovery from COVID 2. Prevent TB 3. Detect TB 4. Control TB 5. Workforce